This invention relates to a lens mounting assembly. More particularly, this invention relates to such an assembly including cooling passages therein for peripherally cooling the lens in, e.g., a laser lens application.
High-powered laser beams are finding increasing application in manufacturing industry where they are used to perform a cutting torch or welding function on a workpiece. The rather high-powered lasers use a generated laser beam which is focused or concentrated at the workpiece by means of a lens. Typically, the lens is made of a zinc selenide material. In passing through the lens, the laser beam loses some of its energy which results in an increase in temperature of the lens. This is disadvantageous in that large thermal stresses frequently occur in the lens resulting in cracking and breakage of the lens itself.
Therefore, it is desirable to have some means for cooling the laser lens and preventing an unwanted heating thereof. Advantageously, a gas is also used in the aforementioned cutting operation to assist in cutting and removing the material being cut. This gas generally is admitted to the region such that it first passes over the lens and then exits through a nozzle coincident with the laser beam and impinges upon the workpiece being cut or welded. In addition to very greatly assisting the cutting, removing, or shielding the material being cut or welded, assisting in keeping dirt and dust from depositing on the lens, the gas also functions to convectively cool the lens by passing thereover. The system using the gas for this cooling purpose is shown in U.S. Pat. No. 3,696,230 to Friedrich.
While the system shown in the Friedrich patent is relatively successful for certain laser power outputs, it does not provide sufficient cooling as higher power outputs are encountered. These higher power outputs are a natural progression from initial attempts at welding and cutting smaller workpieces to using lasers to cut and join larger workpieces.
Other patents of interest are U.S. Pat. Nos. 3,597,578 to Sullivan, and 3,569,660 to Houldcroft. However, these patent devices share the deficiency of the aforementioned patent when higher power applications are encountered.